Coating apparatus



Feb. 16, 1960 J. SCHWINDT comma APPARATUS Filed Oct. 8, 1956 2Sheets-Sheet 1 IN VEN TOR. JOHA NNES S C HW/NDT BY m,mm

A T TOPNEKS- Feb. 16, 1960 J. SCHWINDT comma APPARATUS 2 Sheets-Sheet 2Filed Oct. 8. 1956 INVEN TOR. JOHANNES" SCI IWINDT m ww A TTORNE )"5 W,WwM-B M,

COATING APPARATUS Johannes Schwindt, Langendiebach, Kreis Hanan,Germany, assignor to W. C. Heraeus, G.m.b.H., Hanan, Germany, a Germancompany Application October 8, 1956, Serial No. 614,651

Claims. (Cl. 118-49) This invention relates to vacuum coating, and moreparticularly to apparatus for vacuum'coating' elongated strip materialwhich can be rolled on and off storage reels.

Originally, in the continuous uninterrupted coating of strip material,such as long sheets of plastic, metal, paper, and cloth, by evaporationor by cathode sputtering of a metal or dielectric material, the roll ofmaterial to be coated was loaded directly into a high vacuum chamberwhere the coating operation was performed. This procedure suflered fromthe'disadvantage that each time a new roll was introduced, the coatingchamber had to be vented to the atmosphere and then re-evacuated. Sucha. procedure required an extraordinarily long time for evacuation, andadversely affected the economy of the operation. To avoid thisdifiiculty, it was subsequently proposed that the uucoated, as well asthe coated, roll of material be located outside the coating chamber, andthe strip material be introduced and removed through small slits leadinginto and out of the coating chamber. To compensate for the greatpressure difierence between the outer atmosphere and the pressure in thevacuum chamber, a series of vacuum locks are used to provide stepwisedecreasing pressures' However, this arrangement results in the loss ofcompactconstruction which is detrimental to the commercial and practicalvalue of the system. In addition, the size of the slits of the previousequipment have not been readily adjustable to accommodate variousconditions which may be subject to wide variation, such as varyingthickness of the sheet material which is to be coated, and the differentpressures which may be required to establish the necessary vacuum forthe coating operation.

The present invention provides vacuum coating apparatus for stripmaterial which is compact, of economical construction, and easilyoperated under a wide variety of conditions.

Briefly, the invention contemplates apparatus for vacuum coating stripmaterial which includes a vacuum coating chamber having an inlet and anoutlet. Means are provided for moving the strip material into thecoating chamber throughthe inlet and out of the coatingchamberthroughthe outlet. A separate series of vacuum locks areconnected to the coating chamber inlet and outlet, and means areprovided for forming a slit at each end of the locks through which thestrip material passes.

2,925,062 a Patented-Feb. 15,1960

These and other aspects of the invention will be more fully understoodfrom the following detailed description taken in conjunction with theaccompanying drawings in which:

Fig. 1 is a schematic sectional elevation showing the presentlypreferred embodiment of the invention; and

Fig. 2 is a schematic sectional elevation of an alternate embodiment ofthe invention.

Referring to Fig. l, the coating apparatus includes a horizontalcylindrical storage chamber 12, and a horizontal cylindricalintermediate chamber 14 disposed below and in the same vertical plane asthe storage chamber. A- vertical conduit15 of square cross sectionconnects the.

intermediate chamber to the storage chamber. The storagechamber includesa bottom half 16 and a top half 17 which are held together by bolts 18and flangesv A horizontal cylindrical coating chamber 20 is disposedimmediately below and in the same vertical plane as the intermediatechamber and is. connected to the intermediate chamber by a short duct 21of square cross section. The coating chamber-is connected through avalve 22 to a high vacuum system 24 which includes a difiusion pump 26and a fore-vacuum pump -28. Thestorage chamber,

is connected through a valve 30 to a vacuum pump31.

A double-walled rotatable guide cylinder 32 is coaxially supportedwithin the intermediate chamber by suitable journals (not shown) andspaced therefrom so that an annular space 33 is formed between theintermediate chamber and the guide cylinder. Four equally angular spacedand radially extending electromagnets 34 are disposed within therotatable guide cylinder with their inner" I cylindermay be heated orcooled. as required.

Theaniiulzir space between the intermediate chamber and the;"g'uidecylinder on the left-hand side (as viewed in Fig. l) of theapparatus is divided into two inlet lock chambers 40 by three radiallyextending inlet lock gates 42, each of which is attached at its outerend to the inside surface of the intermediate chamber. Preferably, eachlock gate includes a partition 44 which is a relatively thick and stillbut resilient strip of flexible material such as rubber. Each partitionextends for the length of the intermediate cylinder and is suitablysealed against the ends of the intermediate chamber. Each partition ismolded at its outer end to an elongated longitudinal boss 46 secured tothe interior of the intermediate chamber. The inner end of eachpartition is covered by a metallic shoe 48 whichhas a concave curvatureto match the Means exterior ofthe locks are provided for adjusting thesize of the slits so that the clearance between the slits and the stripmaterial moving through them may readily tight conduit means, throughwhich the strip material are provided forl evacuating the storagepasses, and means chamber. '5

periphery of the guide cylinder. A separate thrust rod 50 extendsradially through the intermediate chamber and each boss and partition,so that the inner end of each thrust rod bears a'gainst. a respectiveshoe. The portion of each rod passing through its respective boss isthreaded so that when the rod is turned by means of a handle 52 attachedto its outer end, the length of the partition may be changed to adjustthe spacing between the shoe and the periphery. of the guide cylinder.Thus, the shoe on the inner end of each inlet partition forms anadjustable inlet slit 53 with an adjacent portion of the guide cylinder;

Two outlet lock chamber 54 are formed in the annular space between theintermediate chamber andthe guide" cylinder on the right-hand side'ofthe apparatus by three outlet lock gates 56 which are constructed in thesameof the apparatus shown in Fig. 1. Each lock gate of the apparatus ofFig. 2 includes a fixed vertical lower partition 150 which extendsacross the duct in a direction perpendicular to the direction of travelof strip material. The fixed partition is bonded at its lower edge tothe bottom of the duct and at each end to the sides of the duct. The topedge of the fixed partition terminates just below the center of theduct.

A flexible and adjustable vertical upper partition 152 is disposed inthe upper portion of the duct to lie in the same plane as the fixedpartition. The upper edge of the ductis bonded to a supporting bar 154whch is sealed to the upper surface of the duct, and the side edges ofthe upper partition make a smooth and sealing fit against the sides ofthe upper portion of the duct. The lower edge of the upper partition hasa protective metal shoe 156, which formsa narrow slit'158 with theadjacen por- -ion of the fixed partition.

An extension rod 159 extends down from the exterior of the top of theduct, through. the duct, throughthe supporting bar, and through theupper partition so thatthe lower end of the rod bears against the uppersurface of the shoe. passes through the support bar so that when it isturned by means of a handle 160 attached to its upper end, it adjuststhe length of the flexible partition, and thereby controls the size ofthe slit.

The supply and take-up chambers are evacuated by means of a pump 162which is connected to the outer end of the inlet and outlet ducts byconduits 164 and 165, respectively. The inlet lock formed between thetwo inlet lock gates nearest the supply chamber and the outlet lockformed between the two outlet lock gates nearest the take-up chamber areevacuated by a pump 168 connected to the inlet and outlet locks byconduits 170 and 172,.respectively. The inlet lock nearer the coatingchamber and the outlet lock nearer the coating chamber are evacuated bya pump 174 through conduits 176 and 178, respectively.

The coating chamber is evacuated through a main valve 180 connected to adiffusion pump 182 and a fore pump 184.

The operation of the apparatus of Fig. 2 is similar to that of Fig. 1.To place the apparatus of Fig. 2 into operation, the supply chamber isopened and a supply reel of strip material is inserted as shown in Fig.2. The leading edge of the strip material is led from the supply reelover the first idling roller, through the first pair of guide rollers,and is guided by means of a metal strip attached to its leading edgethrough the inlet slits. Through suitable access ports (not shown), thestrip is guided through the coating chamber and through the outletslits. The strip is then threaded through the guide rollers in thetake-up chamber, carried around the idler roller and connected to thetake-up reel in the take-up chamber. The system is then made vacuumtight and evacuated to the required pressure.

Once the desired pressure is reached, the reels are actuated to pass thestrip material through the coating chamber in the direction indicated bythe arrows, the slits being adjusted to the necessary clearance toprevent excess leakage from one zone to another and yet providesufiicient clearance to permit free passage of the strip materialthrough the slit without danger of me chanical damage to the material.

When the strip material on the take-up reel is nearly exhausted, theinlet locks are closed against the strip material on the take-up reel.The supply chamber is then opened and the trailing end of the stripmaterial is removed from the supply reel, which is replaced by a newsupply reel with new strip material. The leading end of the new stripmaterial is then cemented to the trailing end of the old strip materialand the supply chamber is closed and evacuated. The new material ispulled through the apparatus by the old material, the slits Theextension rod is threaded where it.

being adjusted to the necessary width. When the new material is in thetake-up chamber, the exit slits are closed and the take-up chamber isopen. The old material is cut from the new, and the leading end of thenew material is connected to a new take-up reel, which replaces the oldtake-up reel. The take-up chamber is then again closed and evacuated,and the exit slits are adjusted to the proper size. The operation thenproceeds as previously described. 1

With the apparatus of this invention, the evacuation of the stripmaterial is sufliciently good, and the move ment of the strip materialthrough the coating chamber is sufliciently low, to avoid thepossibility of evolved gas being trapped during the winding of the stripmaterial on the take-up reel to form air pillows or pockets which wouldresult in a slippage of individual layers of strip material over eachother, resulting in possible damage to the coating.

Another advantage of the apparatus of this invention is that it is ofcompact construction and requires only a limited working space withoutsacrificing facility of operation and inspection. In particular, thecontrols-for the lock gates are readily accessible from the exterior ofthe apparatus and can be adjusted during the operation of the apparatus,so that the sizes of the slits can be adapted not only to the thicknessof the sheet material but also according to the required pressures.Moreover, as soon as a sufficiently high vacuum is produced in theapparatus, the sizes of the slits can be made larger in the high vacuumrange (due to the relatively low rate of gaseous flow through narrowslits at low pressure) so that the danger of damaging thesurface of thestrip material is substantially reduced. Moreover, the adjustability ofthe slit sizes permits the strip material to be changed withoutdisturbing or interrupting the high vacuum in the coating chamber.

I claim: r

1. In apparatus for vacuum coating strip material, the combination whichcomprises a vacuum chamber having an inlet conduit and an outletconduit, each of said conduits having at least one lock chamber, meansfor moving the strip material into the coating chamber through the inletlock chamber and out of the coating chamber through the outlet lockchamber, at least one adjustable partition disposed in each of the inletand outlet conduits for each lock chamber so that each partition definesone side of a respective slit through which the strip material passes, aseparate adjustable extension rod sealed through each of the conduitsand attached at its inner end to a respective partition to provide meansfor moving its respective partition toward and away from the stripmaterial, means for evacuating the coating chamher, and means forintroducing a vaporized coating material into the coating chamber.

2. Apparatus according to claim 1 in which the partitions are made of anelastic material, a shoe is attached to the portion of the partitionwhich defines one side of the slit, and the extension rod extendsthrough the partition so that the inner end of the rod terminatesadjacent the side of the shoe attached to the partition.

3. In apparatus for coating strip material, the combination whichcomprises a storage chamber, an intermediate chamber, a first ductconnecting the storage and intermediate chambers, a coating chamber, asecond duct connecting the intermediate and coating chambers, a guidecylinder disposed within and spaced from the walls of the intermediatechamber, a plurality of adjustable partitions attached to the interiorof the intermediate chamber and extending inwardly to terminate adjacentthe guide cylinder so that a slit is formed between the inner portion ofeach partition and the adjacent portion of the guide cylinder, thepartitions being disposed to divide the space between the guide cylinderand intermediate chamber into locks which isolate the ducts from meansexterior of the intermediate chamber for moving the partitions towardand away from the guide cylinder, means forevacuating the cylinders, andmeans for introducing a vaporized coating material into the coatingchamber.

4. Apparatus according to claim} in which the guide cylinder isrotatable.

5. Apparatus according to claim 4 which includes a plurality ofelectromagnets disposed within the guide cylinder and adapted to attractmagnetic material to the guide cylinder.

6. Apparatus according to claim 3 which includes means for generating arevolving magnetic field'in the intermediate chamber.

7. In apparatus for coating strip materia l, the cornbination comprisinga supply chamber, a coating chamber, an inlet duct connecting the supplyand coating chambers, a take-up chamber, an outlet duct connecting thecoating and take-up chambers, means for moving the strip material fromthe supply chamber through the inlet duct, the coating chamberQtheoutletduct, and into the take-up chamber, a separate set of lock gatesin the inlet and outlet ducts, the gates having adjustable openingsthrough which the strip material passes, means exterior of the ducts foradjusting the size openings of the lock gates, means for evacuating thechambers, and means for introducing a vaporized coating material intothe coating chamber.

8. In apparatus for vacuum coating strip material, the combinationwhichcomprises a vacuum coating chamber having an inlet and an outlet,means for moving the strip material into the coating chamber through theinlet and out of the coating chamber through the outlet, a separateseries of locks connected to the coating chamber inlet and outlet, meansforming a slit in each of the locks through which the strip materialpasses, means exterior of the locks for adjusting the size of the slits,means for evacuating the coating chamber, means for introducing avaporized coating material into the coating chamber, a storage chamberfor the strip material, and vacuum tight conduit 8 means connecting thestorage chamber to the coating. chamber. V

9. In an apparatus for vacuum coating strip material, 5 the combinationwhich comprises a vacuum coating chamber having an inlet and anoutlet,means for moving the strip material into the coating chamber through theinlet and out of the coating chamber through the outlet, a separateseries of locks connected to the coating chamber inlet and outlet, meansforming a slit in each of the locks through which the strip materialpasses, an adjustable extension rod connected individually to each ofsaid slit-forming means for adjusting the size of the slits, each ofsaid extension rods extending to the exterior of the locks, means forevacuating the coating chamber and means for introducing a vaporizedcoating material into the coating chamber.

10. In an apparatus forvacuum coating strip material, the combinationwhich comprises a vacuum chamber having an inlet conduit and an outletconduit, means for moving the strip material into the coating chamberthrough the inlet andout of the coating chamber through the outlet, atleast one adjustable partition disposed in each of the inlet and outletconduits so that each partition defines one side of a respective slitthrough which the strip material passes, a threaded extension rod sealedthrough each of the conduits and attached at its inner end to arespective partition whereby when the extension rod is turned thepartition connected thereto will move toward or away from the stripmaterial, means for evacuating the coating chamber and means forintroducing a vaporized material into the coating chamber,

References Cited in the file of this patent UNITED STATES PATENTS"

